1. Field of the Invention
The present invention relates to a wall mounted microwave oven and a control method therefor, more particularly, to a wall mounted microwave oven and a control method therefor, capable of stopping power supply to a hood fan by a user while said hood fan is automatically being turned on by a hood sensor switch due to increased ambient temperature. With this, unnecessary consumption of the power can be avoided and noise generated from operation of said hood fan can be reduced
2. Prior Art
As illustrated in FIG. 1, a wall mounted microwave oven is mounted on a wall above a gas range 50, and serving as a hood, has a function of inhaling vapor and fumes generated while food is being cooked in the gas range 50. As shown in FIGS. 1 and 2, the wall mounted microwave oven is comprised of a body 3 having a cavity 4 in which the food are cooked, and a casing 6 surrounding the body 3. A magnetron 30 which supplies high frequency electromagnetic waves into the cavity 4 is mounted between said cavity 4 and said casing 6. The magnetron 30 receives a high-tension current through a high-voltage transformer (not shown) and a high-voltage capacitor (not shown).
Meanwhile, the casing 6 includes an upper casing 6a surrounding the upper portion of the body 3 and a lower casing 6b combined with the lower portion of the body 3. A hood duct 15 as a path for exhausting vapor and fume is formed in the space between the casing 6 and the body 3. An inlet port 8 for inhaling vapor and fumes into the hood duct 15 is formed on the lower casing 6b and an outlet port 9 is formed on the upper surface of the upper casing 6a. An exhaust pipe 11 is connected to said outlet port 9. Said exhaust pipe 11 is connected to an exhaust path 17 penetrating the wall to communicate with the air. A hood fan 13 is installed in the upper portion of the body 3 in the vicinity of the outlet port 9, to exhaust the vapor and the fume inhaled into the hood duct 15 via the inlet port 8 to the air via the outlet port 9.
From the control panel, a user can choose to operate said hood fan 13 at low speed or at high speed. As being the case, a hood sensor switch is provided in the inlet port 8 or the inner portion of the hood duct 15, so as to supply power to the hood fan 13 or isolate the hood fan 13 from power, according to the sensed temperature of ambient air. Generally, the on- or the off-temperatures for the hood sensor switch are set, so the hood sensor switch can be on or off when the ambient temperature reaches any of the set temperatures.
With reference to the circuit diagram shown in FIG. 3, driving circuit for a wall mounted microwave oven includes: a hood fan motor 20 connected to normal AC power source 61, power switching part 22 for applying or not power to said hood fan motor 20, a selection switching part 23 for selecting whether to drive said hood fan motor 20 at low or high speed, and a hood sensor switching part 27 disposed in parallel with said power switching part 22 for automatically operating said hood fan motor 20 when ambient temperature is over a predetermined temperature. Said selection switching part 23 is connected to a high speed node 23a to operate said hood fan motor 20 at high speed and to a low speed node 23b to operate the same at low speed, according to said controller 10.
Although a user does not wish to operate said hood fan 13, said hood motor 20 automatically starts to operate by said sensing switching part 27 when ambient temperature increases and is over a predetermined temperature (normally 70.degree. C.) due to, e.g., use of a gas range. Said hood fan motor 20 continues to operate (normally for 20 to 30 minutes) until the ambient temperature decreases and is below a predetermined temperature (normally 40.degree. C.).
Even if the user wishes to stop said hood fan motor 20 while said hood fan motor 20 is being automatically operated by said sensing switching part 27, he/she cannot do so because there are provided no means therefor.
Although said hood fan 13 is unnecessary to operate when ambient temperature does not raise any more, the user has to wait until said hood fan 13 automatically stops. In this case, said hood fan 13 is unnecessarily operating until said sensing switching part 27 is opened, thereby causing noise of operation and unnecessary consumption of electric power.